Improvement in founding



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N.PETERS. FHOTOLITHOGRAFHEH. WASHINGTON, D C.

ffy/miar- `UtuTEn STATES PATENT GEErcE.

A. H. EMERY, OF NEV YORK, N. Y.

IMPROVEMENT IN FOUNDING.

Specitication forming part of Letters Patent No. 37,497, dated January27, 1363.

"0 all whom i6 may concern.-

Be it known that l', A. H, EMERY, a civil engineer, of No. 17 VestVashington Place, in the city, county, and State of New York, haveinvented a new and Improved Method of Founding; and I do herebydeclarethat the following is a full and exact description thereof, referencebeing .had to the accompanying drawings, and to theletters of'referencemarked thereon, and making a part of this specification.

Like letters repuesent like parts.

rIhe nature of my invention consists in providing means to regulate thecooling of the different parts of castings in such a manner and to suchan extent that t-he contraction of the metal in cooling shall notdestroy the casting, but in very many cases renderitbeneficial.

In making castings generally of metals, either separately or incombination, it often happens that the form and size is such rthat someparts of the casting cool first, leaving the rest to cool afterward,andthe contraction of these parts cooling last brings ou heavy strains,and produces cavities to such an extent as often to destroy the entirepiece. 'lo

avoid this evil I incase, either partially or wholly, those parts of thecasting which should cool more slowly than they otherwise would, in anenvelope of melted metal heated to a very high degree and separated fromthe casting by a thin mold.

In the founding of cannon the contraction of the metal has alwaysheretofore proved very injurious. My object is not only to counteractthe evil effects of the contraction, but to make such contractionbeneficial. In casting the cannon solid, the external portion of themetal cools rst and performs alarge share of its contraction while theinner portion of the mass is still in the fiuid state, and as the innerportion cools and contracts, its particles affixing themselves to thesurrounding walls, which have been previously formed by the solidicationof the external portion, are caused to recede from the center of themass, and so produce in the interior of the mass cavities to the amountof the contraction in passing from the liquid to the solid state. Assoon as the metal has all assumed the solid state, motion of theparticles relatively to each other ceases, but contraction goes onuntilthe inner portion of the mass is reduced to the same temperature asthe exterior, and the surrounding medium and the excess of contractionof the inner portion over that of the outer produces tensile strains inthe inner mass and compressive strains in the outer mass. For thepurpose of avoiding these evils some persons have endeavored to cool thegun-casting from the interior by circulating water through a hollow coreplaced in the center of the mold for that purpose; but this onlypartially counteracts the evils mentioned, for while the casting iscooling from the interior it is also cooling from the exterior, leavinga portion of the metal between the interior and exterior to cool last,with the same results as in the solid cast gun, though in a less degree.

To enable others skilled in the art to make use of my invention, I willproceed to describe the means by which I accomplish the desired results.

I use, in combination with a hollow core by which the piece is cooledfrom the' interior, an envelope or casing of melted metal heated to avery high degree, which surrounds the whole or any part or portion ofthe casting that may be desirable, and is separated from it by a thinmold, thus keeping the exterior of the casting hot, while it is cooledentirely from the interior or to any such extent as may be desirable,thereby causing the contraction of the metal either wholly or to such anextent as may be desirable to take place in an inward direction, bywhich means the whole mass is made solid and free from pores, and thecontraction of the external portion of the metal onto the interiorportion serves as a reenforce to that portion. In the case of theexterior cooled gun the strains due to contraction act with those ofthepowder to burst the gun, while in the case of a gun which has beencooled from the interior the strains due to contraction are at theinterior surface, where rupi the same in the plane indicated by the liney 1/ inFig. l. Fig. 3 is a vertical section of the mold and envelope ol"metal, indicated by the line z z in Fig. et, which latter is ahorizontal section in the plane indicated by the line w 1r in Fig. 3.

A represents the flask divided centrally and vertically, and largeenough to contain the central mold, B, in which the piece of ordnance iscast, and the surrounding mold-chamber C, which receives and containsthe envelope or casing of molten metal by which the external portion olthe casting in the mold B is kept heated. rFhe mold B, which may be Y ofany suitable materials, is made as thin as is 'consistent with properstrength, that it may be easily heated by the molten metal in thesurrounding chamber C.

a is the gate for filling the mold B, entering it at the center of thebottom, and having a number of passages, I) b, for conveying the metalthereinto at different elevations. The chamber C is furnished internallywith a number of thin flat horizontal annular cores, e c, and verticalradial cores d d. The cores c e c are only connected with its outerwalls, and annular openings j" j" are left between them and the exteriorofthe mold B. The said cores d d are alternately connected both with themold B and the walls of 'the chamber C, the inteavening ones beingconnected only with the outer walls of the chamber C. By this system ofcores the interior of the chamber C is subdivided into a series ofsmaller chainbers, g g, which communicate with each other, and all ofwhich are in communication with an annular chamber, h, provided underthe bottom of the mold B, for the reception of the molten metal pouredinto the gate t'. From the chamber h the molten metal poured in at thegate i is distributed all through the several subdivisions g g of thechamber C. The object of so subdividing 'this chamber is to provideafter the cooling of the metal, mold, and iiask for the breaking1 up ofthe casting which is obtained in the chamber C, such easting being thusformed into a series of blocks of a suitable size to handle and remelt,and connected only by a thin web, which is easily broken by the hammer.

D is the hollow core-barrel closed at the bottom and open at the top.

E is a smaller pipe arranged within D and extending nearly to the bottomthereof for the purpose of introducing water to expedite the cooling ofthe casting by its circulation in contact with the interior ofthecore-barrel D. The tubes D and E are usually made of Wrought-iron D,being coated externally with a wash of clay to keep the casting fromuniting with it.

F is an overflow-pipe to carry away the water introduced through E afterit has been heated by passing in contact with the core barrel D.

In pouring the molten metals in the gates c and @that poured in at thegate fi should be so regulated with that poured in at the gate ay thatthe metal in the chamber C shall be a few inches higher than that in themold By so that the heat consumed in heating the mold B shall be'takenfrom the metal in the chamber C, and not from the casting in the mold B.The height of the metal in the chamber C must not exceed that in themold B more than a few inches, as the mold Bis very light. The relativeheight in each can be determined by the use of floats. The metal pouredin the chamber O should be made very hot, as it will then require to beof less thickness that if not so much heated; For the same reason themetal in the mold B should not be poured very hot, as the hotter it isthe more metal will be required in the chamber C to insure the coolingofthe casting in the mold B from the interior.

I provide, as in other modes of casting, what is termed a sinkingheadW-that is to say, make the mold deeper than is required for thelength of th`e gun-and thus make the casting extend some distance abovethe part that is to form the muzzle, the metal in the said extendedportion of the casting being intended to supply, while in the fluidstate,1netal to the lower part of the casting equal to the contractionin passing from the fluid to the solid state.

That the sinking head may remain lluid as long as possible and thusperform properly itsfunctions I make the upper end of thev corebarrel Dwith a sleeve, k, made of sand, clay, and plaster-of-paris, eitherseparately or in combination, or of an y other suitable materials, sothat it may cool the sinking head as little as possible. This sleeve 7smay be continued down into the chase of the gun to prolong the coolingsomewhat of that part and thereby lessen the longitudinal strain, and atthe same time assist in longer keeping up the supply of melted metal tothe contracting mass below it.

Ido not make the sinking head as deep as is necessary in other processesof casting, .neither do I find 1t necessary to make the casting ior thegun excessively large about the chase o1' the gun as in other processes,where such exv4 cess has to be turned oft1 at great expense, but cast mygun but a little larger than it is when finished; second, in thefounding of solid shot and shells either elongated or spherical,when oflarger caliber, we find the saine diiiiculties arising from contractionas in the case of guns, and I overcome them'in the same way that ll doin that case. rlhe cavities formed displace the center of gravity oftheprojectile,and thus injure the accuracy of fire, while the cavities andthe strains due to contractioinboth weaken the shot and impair itseffectiveness in the destruction of fortifications, ships7 armor, &c.

This process of founding projectiles is illustrated in Figs. 5 and6,which are central sections, at right angles to each other, of a flaskcontaining a mold and casting and the sur rounding envelope of metal. Inthese figures,

G is the liask; H, the mold, having a very thin Wall, which separatesthe casting for the projectile from the chamber I, which receives theouter envelope or casing of molten metal, by which the cooling of theshot is retarded. The chamber I is subdivided by numerous thin latcores,Z Z m m, in the same manner and for the same purpose as Were thecores e c and d r1 in chamber C of the gun-mold. (See Figs. l, 2, 3, and4.)

m is the gate for the purpose ot' conveying metal into the central moldin which the shot is cast, and n the gate which conveys molten metal tothe chamber I.

p is a small hole through the Wall of the mold H, which conveys metalfrom the chamber I into the mold H as the lmetal in the latter contacts.

K is the hollow core of Wrought-iron, coated externally with clay whenused in the shell, but not so coated when used in a casting intended fora solid shot.

L isa tube passing from the core k through the mold H and chamber I andthe iiask G, and is coated externally with clay.

M is a tube passing into the core k for the purpose of conveying air,steam, or water into the latter, the pipe L conducting the same awayagain. Then the shot is cool, the tube L is removed, and the core 7tandthe cavity left by the removal of the tube L poured full of moltenmetal, leaving the project-ile solid. If it is desired to be used as ashell, the core l.: is made larger than otherwise, and may, if desired,be removed, and the cavity is retained.

In all cases of internal cooling the thickness of the exterior casing orenvelope will be modified by the rapidity with which We conduct away theheat from the interior, being least when water is circulated through theinterior core, and thicker when Water is not so circulated; and in allcases the thickness and heat of the exterior casing of metal should beso regulated in proportion as no't to bring too great strain upon theexterior of the casting of the gun or projectile.

Having thus described my invention,what I claim, and desire to secure byLetters Patent, 1s-

1. The process of retarding the cooling of any part or portion of acasting during the process of founding by means of a casing or envelopeof melted metal covering or surround A. H. EMERY.

fitnessesz E. COHEN, M. C. GRIrz-NER.

